JPH09179301A - Positive radiation-sensitive composition - Google Patents

Abstract

(57) Abstract: The present invention has a high resolution capable of supporting half-micron lithography using light in the far-ultraviolet region, and has good stability with respect to the delay time between exposure and post-exposure bake. Another object of the present invention is to provide a chemically amplified positive photoresist. SOLUTION: A positive feeling is obtained by containing as a main component a resin A containing a structural unit (I), a resin B containing a structural unit (II) and a compound C which generates an acid by radiation such as light or electron beam. Radioactive composition. Embedded image (In the above formula, R ¹ , R ² , R ³ , R ⁷ , R ⁸ and R ⁹ represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and R ⁴ and R ⁵ represent a hydrogen atom or 1 carbon atom. And R ⁶ and R ¹⁰ each represent an alkyl group having 1 to ¹⁰ carbon atoms, and R ⁴ and R ⁵ or R ⁴ and R ⁶ are bonded to each other to form an alkyl group having 3 to 10 carbon atoms. May form a ring.)

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention generally relates to a radiation-sensitive positive-working radiation-sensitive composition, and more specifically, the present invention relates to two types of resins containing a specific structural unit and light or electron beams. The present invention relates to a radiation-sensitive composition containing, as a main component, a compound C that generates an acid by the irradiation of radiation and having excellent resolution and stability.

[0002]

2. Description of the Related Art As the degree of integration of a semiconductor integrated circuit is generally increased four times in three years as generally known, for example, dynamic random access memory (DR)
AM) as an example, full-scale production has started at present with a storage capacity of 4 Mbits. Along with this, the demand for photolithography technology, which is indispensable for the production of integrated circuits, is becoming more and more strict. For example, the production of 4M bit DRAM requires a lithography technology of 0.8 μm level, and higher integration is required. In the advanced 16M DRAM, 0.5 μm level,
It is expected that a lithography technology of 0.35 μm level will be required for 64M DRAM. Along with this, the wavelength used for exposing the resist is also changed from the g-line (436 nm) to the i-line (365 nm) of the mercury lamp, and the K-line.
The wavelength has been shortened to rF excimer laser light (248 nm). However, the conventional positive photoresist using naphthoquinonediazide as a photosensitizer has a very low transmittance for light in the far ultraviolet region such as KrF excimer laser light, resulting in low sensitivity and low resolution.

In order to solve such a problem, as a new positive type resist, there is a chemically amplified positive type photoresist composed of a photo-acid generator and a compound whose solubility in an alkali developing solution is increased by an acid-catalyzed reaction. Various proposals have been made. However, in order to obtain high resolution in such a chemically amplified positive photoresist, it is very important to select a structure of a compound that increases the solubility in an alkali developing solution by an acid-catalyzed reaction. Further, as a peculiar problem in the chemically amplified positive photoresist, exposure and post exposure bake (post exposure,
There is a problem of stability with respect to the resting time with respect to baking. That is, when a time is left between the exposure and the post-exposure bake, the resist film surface in the exposed portion becomes insoluble in the alkaline developer, and the resolution of the resist is often reduced.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to have a high resolution capable of supporting half-micron lithography using light in the far ultraviolet region, which has solved the above-mentioned problems of the prior art, and has an exposure and post-exposure bake. Another object of the present invention is to provide a chemically amplified positive photoresist having good stability with respect to a leaving time between and.

[0005]

In order to increase the resolution of a chemically amplified positive type photoresist, the acid generated by exposure acts effectively to increase the alkali solubility change of the resist film with respect to the exposure amount. It is necessary to. In addition, one of the causes of the phenomenon that the resist film surface of the exposed portion after exposure becomes insoluble in an alkali developing solution is that in a chemically amplified positive resist, the resist film is generally catalyzed by a small amount of acid generated by exposure. Image formation is carried out by a mechanism in which the protective group imparting alkali-insolubility is cleaved to become alkali-soluble, and this deprotecting group reaction mainly proceeds in the post-exposure baking step. That is, after the exposure, before the deprotection group reaction proceeds,
A small amount of acid generated by exposure is deactivated by basic impurities in the air, and the acid concentration on the surface of the resist film is insufficient, so that it becomes insoluble in alkali and the resolution of the resist is lowered.

In order to solve this problem, the kind of protecting group and its elimination that allow the deprotecting reaction to proceed sufficiently before the trace amount of acid generated by exposure is deactivated by the basic impurities in the atmosphere. As a result of diligently studying the selection of the protective group which is easy to be removed, focusing on the reactivity, the use of two kinds of resins containing a specific structural unit has a higher resolution than that which has been conventionally used, and the exposure It was found that a chemically amplified positive photoresist composition having good stability against the post-exposure bake time can be obtained, and the present invention was completed.

That is, the gist of the present invention is to provide structural unit (I)
A containing A, a resin B containing a structural unit (II), and a compound C generating an acid by radiation such as light or electron beam.
A positive-type radiation-sensitive composition characterized by containing as a main component.

[0008]

Embedded image

(In the above formula, R ¹ , R ² , R ³ , R ⁷ , R ⁸ ,
And R ⁹ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, R ⁴ and R ⁵ represent a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and R ⁶ and R ^{10 each} have 1 to ¹⁰ carbon atoms. Represents an alkyl group. In addition, R ⁴ and R ⁵ or R ⁴ and R ⁶ may be bonded to each other to form a ring having 3 to 10 carbon atoms. )

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below.
In the present invention, the resin A is a resin containing the structural unit (I), and the exposed portion becomes alkali-soluble during development,
Any substance that can be dissolved in an alkaline developer and has a uniform resist film-forming ability can be used. For example, a resin obtained by polymerization of hydroxystyrene alone or copolymerization of hydroxystyrene and various vinyl monomers. It is possible to use an acetalized or ketalized part of the hydroxyl group derived from hydroxystyrene.
As the vinyl monomer copolymerized with hydroxystyrene, acrylic acid, vinyl alcohol, or derivatives thereof are used. As the resin A, it is particularly preferable that a part of the hydroxyl groups of polyvinylphenol is represented by the above formula (III).
The resin protected with is used.

In the case of polyvinylphenol, specifically, o-hydroxystyrene, m-hydroxystyrene, p-hydroxystyrene, 2- (o-hydroxyphenyl) propylene, 2- (m-hydroxyphenyl).
A resin obtained by polymerizing hydroxystyrenes such as propylene and 2- (p-hydroxyphenyl) propylene alone or in combination of two or more in the presence of a radical polymerization initiator, an anionic polymerization initiator or a cationic polymerization initiator is used. Further, a resin which has been subjected to hydrogenation in order to reduce the absorbance of the resin after polymerization may be used. The weight average molecular weight of polyvinylphenol is 1,000 to 10 in terms of polystyrene (measured by gel permeation chromatography).
It is preferably 10,000 or more and 7,000 or more and 60,000 or less, more preferably 9,000 or more and 60,000 or less. If the molecular weight of polyvinylphenol is smaller than this range, a sufficient coating film as a resist cannot be obtained, and the heat resistance also deteriorates. If it is larger than this range, the solubility of the exposed part in an alkaline developing solution becomes small, and the resist Pattern cannot be obtained.

When the resin A containing the structural unit (I) is a resin in which a part of hydroxyl groups of polyvinylphenol is protected by the formula (III), a δ value of 6.0 derived from aromatic hydrogen in a proton NMR spectrum is obtained. The peak area up to 7.2 and the δ value of 5.0 to 5. derived from hydrogen of the acetal group.
It is preferable that the ratio of the peak area up to 6 is 8: 1 or more and 40: 1 or less. In the structural unit (I), R ⁴ and R ⁵ are hydrogen atoms or an alkyl group having 1 to 10 carbon atoms, and R ⁶ is an alkyl group having 1 to 10 carbon atoms, R ⁴ and R ⁵ or R ⁴ And R ⁶ are bonded to each other to have a carbon number of 3 to
Although it may form 10 rings, R ⁴ is preferably an alkyl group having 1 to 10 carbon atoms, R ⁵ is a hydrogen atom, and R ⁶ is an alkyl group having 1 to 10 carbon atoms.

The resin B is a resin containing the structural unit (II), and as in the case of the resin A, if the exposed portion becomes alkali-soluble during development and elutes in an alkali developing solution and has a uniform resist film forming ability. Although anything can be used, for example, it is possible to use a resin obtained by polymerizing hydroxystyrene alone or copolymerizing hydroxystyrene with various vinyl monomers and partially carbonizing a part of hydroxyl groups derived from hydroxystyrene. . As the vinyl monomer copolymerized with hydroxystyrene, acrylic acid, vinyl alcohol, or derivatives thereof are used. As the resin B, a resin in which a part of the hydroxyl groups of polyvinylphenol is protected by the above formula (IV) is particularly preferably used. The rate of introduction of the protective group can be estimated by the rate of weight loss due to thermal decomposition. Usually, these carbonate groups are decomposed and eliminated at about 50 ° C to 250 ° C, which is lower than the decomposition temperature of the polymer main chain. To do.
In the positive-type radiation-sensitive composition of the present invention, the weight reduction rate due to the decomposition of the carbonate group at 50 ° C. to 250 ° C. is preferably 10% or more and 40% or less, more preferably 15% or more and 30% or less. . If the weight reduction rate is less than this range, the difference in dissolution rate in the alkali developing solution before and after exposure becomes small, and the resolution of the resist decreases.
If the weight reduction rate is larger than this range, a large amount of acid is required to remove the carbonate group after exposure, and the acid is easily affected by deactivation of the acid during storage after exposure.

In the case of polyvinylphenol, specifically, o-hydroxystyrene, m-hydroxystyrene, p-hydroxystyrene, 2- (o-hydroxyphenyl) propylene, 2- (m-hydroxyphenyl).
A resin obtained by polymerizing hydroxystyrenes such as propylene and 2- (p-hydroxyphenyl) propylene alone or in combination of two or more in the presence of a radical polymerization initiator, an anionic polymerization initiator or a cationic polymerization initiator is used. Further, a resin which has been subjected to hydrogenation in order to reduce the absorbance of the resin after polymerization may be used. The weight average molecular weight of polyvinylphenol is 1,000 to 10 in terms of polystyrene (measured by gel permeation chromatography).
The number of those used is 10,000, preferably 1,000 or more and 60,000 or less. If the molecular weight of polyvinylphenol is smaller than this range, a sufficient coating film as a resist cannot be obtained, and the heat resistance also deteriorates. If it is larger than this range, the solubility of the exposed part in an alkaline developing solution becomes small, and the resist Pattern cannot be obtained.

As the compound (photoacid generator) C which generates an acid by radiation such as light or electron beam, any compound can be used as long as it can generate an acid by light or electron beam used for exposure. Specifically, for example, tris (trichloromethyl) -s-triazine, tris (tribromomethyl) -s-triazine, tris (dibromomethyl) -s-triazine, 2,4-bis (tribromomethyl)- 6-p-methoxyphenyl-s
-Halogen-containing s-triazine derivatives such as triazine, 1,2,3,4-tetrabromobutane, 1,1,
Halogen-substituted paraffinic hydrocarbons such as 2,2-tetrabromoethane, carbon tetrabromide, and iodoform; halogen-substituted cycloparaffinic hydrocarbons such as hexabromocyclohexane, hexachlorocyclohexane, and hexabromocyclododecane; bis (trichloromethyl) benzene , Halogen-containing benzene derivatives such as bis (tribromomethyl) benzene, halogen-containing sulfone compounds such as tribromomethylphenylsulfone, trichloromethylphenylsulfone, and 2,3-dibromosulfolane; tris (2,3-dibromopropyl) isocyanurate Such as halogen-containing isocyanurate derivatives, triphenylsulfonium chloride, triphenylsulfonium methanesulfonate, and triphenylsulfonium trifluoromethanesulfate , Sulfonium salts such as triphenylsulfonium tetrafluoroborate, triphenylsulfonium hexafluoroarsenate, triphenylsulfonium hexafluorophosphonate, diphenyliodonium trifluoromethanesulfonate, diphenyliodonium p-toluenesulfonate, diphenyl Iodonium tetrafluoroborate,
Diphenyliodonium hexafluoroarsenate,
Examples include iodonium salts such as diphenyliodonium hexafluorophosphonate.

Further, methyl p-toluenesulfonate, p
-Ethyl toluene sulfonate, butyl p-toluene sulfonate, phenyl p-toluene sulfonate, 1,2,3
-Tri (p-toluenesulfonyl) benzene, p-toluenesulfonic acid benzoin ester, methyl methanesulfonate, ethyl methanesulfonate, butyl methanesulfonate, 1,2,3-tri (methanesulfonyl) benzene, phenyl methanesulfonate Benzoin methanesulfonate, methyl trifluoromethanesulfonate, ethyl trifluoromethanesulfonate, butyl trifluoromethanesulfonate, 1,2,3-tri (trifluoromethanesulfonyl) benzene, phenyl trifluoromethanesulfonate, benzoin trifluoromethanesulfonate Sulfonates such as esters, disulfones such as diphenyldisulfone, di (phenylsulfonyl) diazomethane, di (cyclohexylsulfonyl) diazomethane, etc. Sulfonic diazide compounds, o-o-nitrobenzyl esters such as nitrobenzyl -p- toluenesulfonate, N, may also be mentioned, such as N'- disulfonic hydrazides such as (phenylsulfonyl) hydrazide.

Particularly preferred among these acid generators are:
It is a compound in which the acid generated is sulfonic acid, sulfenic acid, or sulfinic acid. Specifically, onium sulfonates such as triphenylsulfonium p-toluenesulfonate and diphenyliodonium p-toluenesulfonate, phenyl p-toluenesulfonate,
Sulfonates such as 1,2,3-tri (p-toluenesulfonyl) benzene, disulfones such as diphenyldisulfone, sulfonediazides such as di (phenylsulfonyl) diazomethane and di (cyclohexylsulfonyl) diazomethane, o- O-nitrobenzyl esters such as nitrobenzyl-p-toluenesulfonate are preferably used.

In the positive-type radiation-sensitive composition of the present invention, based on 100 parts by weight of the resin A containing the structural unit (I),
1 to 100 parts by weight, preferably 1 to 60 parts by weight of the resin B containing the structural unit (II), 0.01 to 10 parts by weight of the compound C which generates an acid by radiation such as light or electron beam,
It is preferably used in a proportion of 0.1 to 5 parts by weight. When the amount of the resin B containing the structural unit (II) is less than this range, a sufficient change in dissolution rate cannot be obtained between the exposed portion and the unexposed portion, and a good resist pattern cannot be obtained. Also,
If the amount of the resin B containing the structural unit (II) is more than this range, the stability of the storage until the post-exposure bake becomes poor, and sufficient resolution is obtained when the time interval between the exposure and the post-exposure bake becomes long. You won't get it.

When the amount of the compound C which generates an acid by radiation such as light or electron beam is less than this range, the sensitivity becomes extremely low and it is not practical. If the amount of the compound C that generates an acid by radiation such as light or electron beam is larger than this range, the transparency of the resist film is reduced by the photoacid generator, and the resist pattern becomes a trapezoid, which causes a reduction in resolution.

The positive-working radiation-sensitive composition of the present invention is usually prepared by dissolving these resin A, resin B and photoacid generator C in a suitable solvent. The solvent to be used is not particularly limited as long as it is a solvent which has a sufficient solubility in the photo-acid generator and the resin and gives a good coating property.
-Ketone solvents such as hexanone and cyclohexanone,
Cellosolve solvents such as methyl cellosolve, ethyl cellosolve, methyl cellosolve acetate, ethyl cellosolve acetate, diethyl oxalate, ethyl pyruvate, ethyl-2-hydroxybutyrate, ethyl acetoacetate, butyl acetate, amyl acetate, ethyl butyrate, butyl butyrate. , Ester solvents such as methyl lactate, ethyl lactate, methyl 3-methoxypropionate, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monobutyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol Propylene glycol such as monobutyl ether acetate and dipropylene glycol dimethyl ether Le solvents, cyclohexanone, methyl amyl ketone, ketone solvents such as 2-heptanone,
Alternatively, a mixed solvent of these, or a solvent to which an aromatic hydrocarbon is further added may be used. The use ratio of the solvent is preferably in the range of 1 to 20 times as a weight ratio with respect to the total amount of solids in the photosensitizer composition.

When a resist pattern is formed on a semiconductor substrate using the positive-type radiation-sensitive composition of the present invention,
Usually, the positive photosensitive composition of the present invention dissolved in a solvent as described above is applied onto a semiconductor substrate and used as a photoresist through the steps of pre-baking, pattern transfer by exposure, post-exposure baking, and development. be able to. The semiconductor substrate is generally used as a substrate for manufacturing a semiconductor, and is a silicon substrate, a gallium arsenide substrate, or the like. A spin coater is usually used for coating, and 436 nm, 365 nm light of a high pressure mercury lamp, 254 nm of a low pressure mercury lamp, 157 nm, 193 nm, 222 nm, 248 nm light or an electron beam using an excimer laser as a light source is suitable for exposure. Used for. Light at the time of exposure may be broad instead of monochromatic light. Further, exposure by the phase shift method can also be applied.

The developer of the positive photoresist composition of the present invention contains sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate,
Inorganic alkalis such as aqueous ammonia, ethylamine, n
Primary amines such as -propylamine, secondary amines such as diethylamine and di-n-propylamine, tertiary amines such as triethylamine, N, N-diethylmethylamine, tetramethylammonium hydroxide, A quaternary ammonium salt such as trimethylhydroxyethylammonium hydroxide, or a quaternary ammonium salt to which an alcohol, a surfactant or the like is added can be used. The positive photoresist composition of the present invention is useful not only for VLSI production but also for general IC production, mask production, image formation, liquid crystal screen production, color filter production or offset printing.

[0023]

EXAMPLES The present invention will be described in more detail with reference to Examples and Synthetic Examples, but the present invention is not limited to the following Examples without departing from the scope of the invention. Synthesis Example 1 (Synthesis of 1-methyl-1-methoxyethylated polyvinylphenol) Polyvinylphenol (weight average molecular weight 414 was added to a 1-liter four-necked flask equipped with a nitrogen inlet tube, a stirrer, and a thermometer.
(00) and 300 ml of ethyl acetate were added and dissolved uniformly, 14.4 g of 2-methoxypropene was added, and the mixture was heated to 40 ° C. in a water bath. In addition, 36
% Hydrochloric acid was added, and stirring was continued for 4 hours. After the reaction,
The reaction solution was extracted with 400 ml of a 1% sodium hydrogen carbonate aqueous solution. The obtained organic layer was dried over anhydrous sodium sulfate and then concentrated to about 100 ml with a rotary evaporator. This concentrated solution was poured into 1 liter of n-hexane to recover the polymer. The precipitated polymer was vacuum dried to obtain 33.2 g of 1-methyl-1-methoxyethylated polyvinylphenol.

Synthesis Example 2 (Synthesis of 1-Ethoxyethylated Polyvinylphenol) Polyvinylphenol (weight average molecular weight 414 was added to a 1-liter four-necked flask equipped with a nitrogen inlet tube, a stirrer, and a thermometer.
(00) and 300 ml of ethyl acetate were added and dissolved uniformly, 14.4 g of ethyl vinyl ether was added, and the mixture was heated to 40 ° C. in a water bath. In addition, 36
% Hydrochloric acid was added, and stirring was continued for 4 hours. After the reaction,
The reaction solution was extracted with 400 ml of a 1% sodium hydrogen carbonate aqueous solution. The obtained organic layer was dried over anhydrous sodium sulfate and then concentrated to about 100 ml with a rotary evaporator. This concentrated solution was poured into 1 liter of n-hexane to recover the polymer. The precipitated polymer was vacuum dried to obtain 36.1 g of 1-ethoxyethylated polyvinylphenol. The obtained polymer was dissolved in deuterated acetone and the proton NMR spectrum was measured. As a result, a signal of aromatic hydrogen having a δ value of 6.2 to 7.0 and acetal methine hydrogen having a δ value of 5.2 to 5.5 were obtained. The area ratio with respect to the signal was 14.85: 1.

Synthesis Example 3 (Synthesis of tetrahydropyranylated polyvinylphenol) Polyvinylphenol (weight average molecular weight 414 was added to a 1-liter four-necked flask equipped with a nitrogen inlet tube, a stirrer and a thermometer.
(00) and 300 ml of ethyl acetate were added and dissolved uniformly, 21.0 g of dihydropyran was added, and the mixture was heated to 40 ° C. in a water bath. To this, 0.3 g of 36% hydrochloric acid was added, and stirring was continued for 4 hours. After the reaction, this reaction solution was extracted with 400 ml of a 1% sodium hydrogen carbonate aqueous solution. The obtained organic layer was dried over anhydrous sodium sulfate and then concentrated to about 100 ml with a rotary evaporator. This concentrated solution was poured into 1 liter of n-hexane to recover the polymer. The precipitated polymer is vacuum dried,
34.3 g of tetrahydropyranylated polyvinylphenol was obtained. The obtained polymer was dissolved in deuterated acetone and the proton NMR spectrum was measured.
Signals of aromatic hydrogen having a value of 6.2 to 7.0 and a δ value of 5.2
The area ratio with the signal of acetal methine hydrogen of -5.5 was 10.81: 1.

Synthesis Example 4 (Synthesis of tert-butoxycarbonyloxylated polyvinylphenol) Polyvinylphenol (weight average molecular weight of 121 was added to a 1-liter four-necked flask equipped with a nitrogen inlet tube, a stirrer and a thermometer.
00) 36.05 g and 150 ml of acetone were added and dissolved uniformly, then 0.01 g of N, N-dimethylaminopyridine was added as a catalyst, and the mixture was mixed with a water bath at 40
Heated to ° C. To this, 17.68 g of di-tert-butyl-di-carbonate was slowly added and stirring was continued for 4 hours. After the reaction, this reaction solution was poured into 1.5 liters of ion-exchanged water to collect the polymer. The polymer was dissolved in 100 ml of acetone and reprecipitated in 1.5 liter of ion-exchanged water to recover the polymer. This polymer was redissolved in 100 ml of acetone, reprecipitated in 1.5 liters of ion-exchanged water to recover the polymer, and then vacuum dried to obtain 44.28 g of tert-butoxycarbonyloxylated polyvinylphenol. When the weight loss rate of the obtained polymer was determined by TG / DTA, a weight loss of 19.2% was observed between 99.7 ° C and 215.1 ° C. (TG / DTA measurement condition: temperature range 3
0-280 ° C, heating rate 10 ° C / min, nitrogen flow rate 100m
l / min)

Example 1 0.35 g of the resin synthesized in Synthesis Example 1, 0.15 g of the resin synthesized in Synthesis Example 4, 0.0175 g of di (cyclohexylsulfonyl) diazomethane as a photoacid generator, and propylene glycol monomethyl ether acetate. 2.7 g was mixed to obtain a resist photosensitive solution. This photosensitive solution was spin-coated on a silicon substrate and baked on a hot plate at 120 ° C. for 90 seconds to form a resist film having a film thickness of 0.75 μm. This resist film on the silicon substrate is subjected to a Nikon KrF excimer laser reduction projection exposure apparatus (NA
= 0.42), and after exposing with an energy amount of 31.5 mJ / cm ² , baking was performed on a hot plate at 80 ° C. for 90 seconds. Thereafter, the resist film was developed with a 2.38% by weight aqueous solution of tetramethylammonium hydroxide for 1 minute. The resolution was evaluated by observing the resist pattern obtained after this development with a scanning electron microscope. As a result, a 0.26 μm line and space was resolved with a good shape.

Example 2 0.35 g of the resin synthesized in Synthesis Example 2, 0.15 g of the resin synthesized in Synthesis Example 4, and triphenylsulfonium p-toluenesulfonate 0.0175 as a photoacid generator.
g and propylene glycol monomethyl ether acetate 2.7 g were mixed to obtain a resist photosensitive solution. This photosensitive solution was spin-coated on a silicon substrate and baked on a hot plate at 120 ° C. for 90 seconds to give a film thickness of 0.75.
The resist film has a thickness of μm. The resist film on the silicon substrate was exposed with a KrF excimer laser reduction projection exposure device (NA = 0.42) manufactured by Nikon Corporation at an energy amount of 24.5 mJ / cm ² , and then 80 on a hot plate.
It was baked at 90 ° C. for 90 seconds. Thereafter, the resist film was developed with a 2.38% by weight aqueous solution of tetramethylammonium hydroxide for 1 minute. The resolution was evaluated by observing the resist pattern obtained after this development with a scanning electron microscope. As a result, 0.26 μm line and
The space was well resolved.

Example 3 0.40 g of the resin synthesized in Synthesis Example 2, 0.10 g of the resin synthesized in Synthesis Example 4, and triphenylsulfonium p-toluenesulfonate 0.0175 as a photoacid generator.
g and propylene glycol monomethyl ether acetate 2.7 g were mixed to obtain a resist photosensitive solution. This photosensitive solution was spin-coated on a silicon substrate and baked on a hot plate at 120 ° C. for 90 seconds to give a film thickness of 0.75.
The resist film has a thickness of μm. The resist film on this silicon substrate was exposed with an energy amount of 17.5 mJ / cm ² by using a KrF excimer laser reduction projection exposure device (NA = 0.42) manufactured by Nikon Corporation, and then 80 on a hot plate.
It was baked at 90 ° C. for 90 seconds. Thereafter, the resist film was developed with a 2.38% by weight aqueous solution of tetramethylammonium hydroxide for 1 minute. The resolution was evaluated by observing the resist pattern obtained after this development with a scanning electron microscope. As a result, 0.26 μm line and
The space was well resolved.

Example 4 0.45 g of the resin synthesized in Synthesis Example 2, 0.05 g of the resin synthesized in Synthesis Example 4, and triphenylsulfonium p-toluenesulfonate 0.0175 as a photoacid generator.
g and propylene glycol monomethyl ether acetate 2.7 g were mixed to obtain a resist photosensitive solution. This photosensitive solution was spin-coated on a silicon substrate and baked on a hot plate at 120 ° C. for 90 seconds to give a film thickness of 0.75.
The resist film has a thickness of μm. The resist film on the silicon substrate was exposed with an energy amount of 13.5 mJ / cm ² using a KrF excimer laser reduction projection exposure device (NA = 0.42) manufactured by Nikon Corporation, and then 80 on a hot plate.
It was baked at 90 ° C. for 90 seconds. Thereafter, the resist film was developed with a 2.38% by weight aqueous solution of tetramethylammonium hydroxide for 1 minute. The resolution was evaluated by observing the resist pattern obtained after this development with a scanning electron microscope. As a result, 0.26 μm line and
The space was well resolved.

Example 5 0.35 g of the resin synthesized in Synthesis Example 2, 0.15 g of the resin synthesized in Synthesis Example 4, 0.0035 g of di (cyclohexylsulfonyl) diazomethane as a photoacid generator, and propylene glycol monomethyl ether acetate. 2.7 g was mixed to obtain a resist photosensitive solution. This photosensitive solution was spin-coated on a silicon substrate and baked on a hot plate at 120 ° C. for 90 seconds to form a resist film having a film thickness of 0.75 μm. This resist film on the silicon substrate is subjected to a Nikon KrF excimer laser reduction projection exposure apparatus (NA
= 0.42), and exposed at an energy amount of 27.5 mJ / cm ² , and then baked on a hot plate at 80 ° C. for 90 seconds. Thereafter, the resist film was developed with a 2.38% by weight aqueous solution of tetramethylammonium hydroxide for 1 minute. The resolution was evaluated by observing the resist pattern obtained after this development with a scanning electron microscope. As a result, the line and space of 0.28 μm was resolved with a good shape.

Example 6 0.35 g of the resin synthesized in Synthesis Example 2, 0.15 g of the resin synthesized in Synthesis Example 4, 0.0175 g of di (cyclohexylsulfonyl) diazomethane as a photoacid generator, and propylene glycol monomethyl ether acetate. 2.7 g was mixed to obtain a resist photosensitive solution. This photosensitive solution was spin-coated on a silicon substrate and baked on a hot plate at 120 ° C. for 90 seconds to form a resist film having a film thickness of 0.75 μm. This resist film on the silicon substrate is subjected to a Nikon KrF excimer laser reduction projection exposure apparatus (NA
= 0.42), and after exposing with an energy amount of 13.0 mJ / cm ² , baking was performed on a hot plate at 80 ° C. for 90 seconds. Thereafter, the resist film was developed with a 2.38% by weight aqueous solution of tetramethylammonium hydroxide for 1 minute. The resolution was evaluated by observing the resist pattern obtained after this development with a scanning electron microscope. As a result, the line and space of 0.30 μm was resolved with a good shape.

Example 7 0.45 g of the resin synthesized in Synthesis Example 2, 0.05 g of the resin synthesized in Synthesis Example 4, 0.0035 g of di (cyclohexylsulfonyl) diazomethane as a photoacid generator, and propylene glycol monomethyl ether acetate. 2.7 g was mixed to obtain a resist photosensitive solution. This photosensitive solution was spin-coated on a silicon substrate and baked on a hot plate at 120 ° C. for 90 seconds to form a resist film having a film thickness of 0.75 μm. This resist film on the silicon substrate is subjected to a Nikon KrF excimer laser reduction projection exposure apparatus (NA
= 0.42), and after exposing with an energy amount of 17.5 mJ / cm ² , baking was performed on a hot plate at 80 ° C. for 90 seconds. Thereafter, the resist film was developed with a 2.38% by weight aqueous solution of tetramethylammonium hydroxide for 1 minute. The resolution was evaluated by observing the resist pattern obtained after this development with a scanning electron microscope. As a result, the line and space of 0.28 μm was resolved with a good shape.

Example 8 0.45 g of the resin synthesized in Synthesis Example 2, 0.05 g of the resin synthesized in Synthesis Example 4, 0.0175 g of di (cyclohexylsulfonyl) diazomethane as a photoacid generator, and propylene glycol monomethyl ether acetate. 2.7 g was mixed to obtain a resist photosensitive solution. This photosensitive solution was spin-coated on a silicon substrate and baked on a hot plate at 120 ° C. for 90 seconds to form a resist film having a film thickness of 0.75 μm. This resist film on the silicon substrate is subjected to a Nikon KrF excimer laser reduction projection exposure apparatus (NA
= 0.42), and after exposing with an energy amount of 17.5 mJ / cm ² , baking was performed on a hot plate at 80 ° C. for 90 seconds. Thereafter, the resist film was developed with a 2.38% by weight aqueous solution of tetramethylammonium hydroxide for 1 minute. The resolution was evaluated by observing the resist pattern obtained after this development with a scanning electron microscope. As a result, the line and space of 0.30 μm was resolved with a good shape.

Example 9 0.45 g of the resin synthesized in Synthesis Example 3, 0.05 g of the resin synthesized in Synthesis Example 4, and triphenylsulfonium p-toluenesulfonate 0.0175 as a photoacid generator.
g and propylene glycol monomethyl ether acetate 2.7 g were mixed to obtain a resist photosensitive solution. This photosensitive solution was spin-coated on a silicon substrate and baked on a hot plate at 120 ° C. for 90 seconds to give a film thickness of 0.75.
The resist film has a thickness of μm. The resist film on the silicon substrate was exposed with an energy amount of 13.5 mJ / cm ² using a KrF excimer laser reduction projection exposure device (NA = 0.42) manufactured by Nikon Corporation, and then 80 on a hot plate.
It was baked at 90 ° C. for 90 seconds. Thereafter, the resist film was developed with a 2.38% by weight aqueous solution of tetramethylammonium hydroxide for 1 minute. The resolution was evaluated by observing the resist pattern obtained after this development with a scanning electron microscope. As a result, 0.26 μm line and
The space was well resolved.

Example 10 The resist photosensitive solution used in Example 4 was spin-coated on a silicon substrate and baked on a hot plate at 120 ° C. for 90 seconds to form a resist film having a thickness of 0.75 μm. The resist film on this silicon substrate was exposed with an energy amount of 34.5 mJ / cm ² using a KrF excimer laser reduction projection exposure apparatus (NA = 0.42) manufactured by Nikon Corporation, and then in air containing 10 ppb ammonia. It was left for 1 hour. After that, the resist film was baked on a hot plate at 80 ° C. for 90 seconds, and this resist film was developed with a 2.38 wt% tetramethylammonium hydroxide aqueous solution for 1 minute. The resolution was evaluated by observing the resist pattern obtained after this development with a scanning electron microscope. As a result, a resist pattern having the same shape as in Example 4 was obtained.

Comparative Example 1 1.0 g of the resin synthesized in Synthesis Example 1 was used as a photo-acid generator.
Di (cyclohexylsulfonyl) diazomethane 0.01
75 g and 5.9 g of propylene glycol monomethyl ether acetate were mixed to obtain a resist photosensitive solution.
This photosensitive solution was spin-coated on a silicon substrate and baked on a hot plate at 120 ° C. for 90 seconds to give a film thickness of 0.7.
The resist film has a thickness of 5 μm. The resist film on the silicon substrate was exposed with an energy amount of 28 mJ / cm ² by using a KrF excimer laser reduction projection exposure device (NA = 0.42) manufactured by Nikon, and then exposed on a hot plate at 80 ° C. for 9 hours.
Bake for 0 seconds. Thereafter, the resist film was developed with a 2.38% by weight aqueous solution of tetramethylammonium hydroxide for 1 minute. The resolution was evaluated by observing the resist pattern obtained after this development with a scanning electron microscope. As a result, a good shape was resolved only up to a line and space of 0.50 μm, and a pattern smaller than this had a significantly low residual film rate.

Comparative Example 2 1.0 g of the resin synthesized in Synthesis Example 2 was used as a photoacid generator.
Triphenylsulfonium p-toluenesulfonate 0.007 g and propylene glycol monomethyl ether acetate 5.9 g were mixed to obtain a resist photosensitive solution. Spin coating this photosensitive solution on a silicon substrate,
The resist film was baked on a hot plate at 120 ° C. for 90 seconds to form a resist film having a film thickness of 0.75 μm. The resist film on this silicon substrate was exposed to 15 mJ / cm ² using a NiF KrF excimer laser reduction projection exposure device (NA = 0.42).
On the hot plate after exposure with 80
It was baked at 90 ° C. for 90 seconds. Thereafter, the resist film was developed with a 2.38% by weight aqueous solution of tetramethylammonium hydroxide for 1 minute. The resolution was evaluated by observing the resist pattern obtained after this development with a scanning electron microscope. As a result, a good shape was resolved only up to a line and space of 0.40 μm, and a pattern smaller than this had a significantly low residual film rate.

Comparative Example 3 1.0 g of the resin synthesized in Synthesis Example 1 was used as a photo-acid generator.
Di (cyclohexylsulfonyl) diazomethane 0.00
7 g and 5.9 g of propylene glycol monomethyl ether acetate were mixed to obtain a resist photosensitive solution. This photosensitive solution was spin-coated on a silicon substrate and baked on a hot plate at 120 ° C. for 90 seconds to give a film thickness of 0.75.
The resist film has a thickness of μm. The resist film on the silicon substrate was exposed with an energy amount of 11.5 mJ / cm ² using a NiF KrF excimer laser reduction projection exposure device (NA = 0.42), and then on a hot plate at 80 ° C.
Bake for 90 seconds. Thereafter, the resist film was developed with a 2.38% by weight aqueous solution of tetramethylammonium hydroxide for 1 minute. The resolution was evaluated by observing the resist pattern obtained after this development with a scanning electron microscope. As a result, a good shape was resolved only up to a line and space of 0.40 μm, and a pattern smaller than this had a significantly low residual film rate.

Comparative Example 4 1.0 g of the resin synthesized in Synthesis Example 3 was used as a photo-acid generator.
Triphenylsulfonium p-toluenesulfonate 0.007 g and propylene glycol monomethyl ether acetate 5.9 g were mixed to obtain a resist photosensitive solution. Spin coating this photosensitive solution on a silicon substrate,
The resist film was baked on a hot plate at 120 ° C. for 90 seconds to form a resist film having a film thickness of 0.75 μm. The resist film on this silicon substrate was set to 10.5 mJ / c by using a NiF KrF excimer laser reduction projection exposure device (NA = 0.42).
After exposure with an energy amount of m ² , the film was baked on a hot plate at 80 ° C. for 90 seconds. Thereafter, the resist film was developed with a 2.38% by weight aqueous solution of tetramethylammonium hydroxide for 1 minute. The resolution was evaluated by observing the resist pattern obtained after this development with a scanning electron microscope. As a result, a good shape was resolved only up to a line and space of 0.55 μm, and a pattern smaller than this had a significantly low residual film rate.

Comparative Example 5 1.0 g of the resin synthesized in Synthesis Example 4 was used as a photo-acid generator.
Triphenylsulfonium p-toluenesulfonate (0.07 g) and propylene glycol monomethyl ether acetate (4.6 g) were mixed to prepare a resist photosensitive solution. This photosensitive solution was spin-coated on a silicon substrate and baked on a hot plate at 120 ° C. for 90 seconds to form a resist film having a film thickness of 0.75 μm. The resist film on this silicon substrate is 100 mJ / cm 2 using a NiF KrF excimer laser reduction projection exposure device (NA = 0.42).
8 on hot plate after exposure with ² energy
It was baked at 0 ° C. for 90 seconds. After that, the resist film was covered with 2.38% by weight of tetramethylammonium hydroxide.
It was developed with an aqueous solution for 1 minute. However, no resist pattern was obtained after development.

Comparative Example 6 1.0 g of the resin synthesized in Synthesis Example 4 was used as a photoacid generator.
Triphenylsulfonium trifluoromethanesulfonate (0.07 g) and propylene glycol monomethyl ether acetate (4.6 g) were mixed to prepare a resist photosensitive solution. This photosensitive solution is spin-coated on a silicon substrate and baked on a hot plate at 120 ° C. for 90 seconds,
A resist film having a film thickness of 0.75 μm was used. The resist film on this silicon substrate was 25 mJ / c using a NiF KrF excimer laser reduction projection exposure device (NA = 0.42).
After exposure with an energy amount of m ² , the film was baked on a hot plate at 80 ° C. for 90 seconds. Thereafter, the resist film was developed with a 2.38% by weight aqueous solution of tetramethylammonium hydroxide for 1 minute. The resolution was evaluated by observing the resist pattern obtained after this development with a scanning electron microscope. As a result, the line and space of 0.40 μm was resolved, but the pattern shape was unsatisfactory because the upper part of the resist was projected like a canopy.

Comparative Example 7 The resist photosensitive solution used in Comparative Example 4 was spin-coated on a silicon substrate and baked on a hot plate at 120 ° C. for 90 seconds to form a resist film having a thickness of 0.75 μm. The resist film on this silicon substrate was exposed with an energy amount of 88 mJ / cm ² using a KrF excimer laser reduction projection exposure device (NA = 0.42) manufactured by Nikon Corporation, and then 1
It was left in the air containing 0 ppb of ammonia for 1 hour.
Then, the resist film was baked on a hot plate at 80 ° C. for 90 seconds, and this resist film was developed with a 2.38 wt% tetramethylammonium hydroxide aqueous solution for 1 minute. However, no resist pattern was obtained after development.

[0044]

The positive-type radiation-sensitive composition of the present invention uses two kinds of resins having different structural units,
While maintaining high resolution, the stability against the delay time between exposure and baking after exposure, which has been a drawback of the conventional chemically amplified positive photoresist, is also good, so that it is of course possible to manufacture highly integrated LSIs. That is, it is extremely useful for other image formation.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Jun Fujita 1000 Kamoshida-cho, Aoba-ku, Yokohama-shi, Kanagawa Mitsubishi Chemical Corporation Yokohama Research Institute (72) Inventor Yuki 1000 Kamoshida-cho, Aoba-ku, Yokohama, Kanagawa Mitsubishi Chemical Co., Ltd. Yokohama Research Institute

Claims (8)

[Claims] 1. A resin containing a structural unit (I), a resin B containing a structural unit (II), and a compound C which generates an acid by radiation such as light or electron beam as main components. Positive radiation-sensitive composition. Embedded image (In the above formula, R ¹ , R ² , R ³ , R ⁷ , R ⁸ and R ⁹ represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and R ⁴ and R ⁵ represent a hydrogen atom or 1 carbon atom. And R ⁶ and R ¹⁰ each represent an alkyl group having 1 to ¹⁰ carbon atoms, and R ⁴ and R ⁵ or R ⁴ and R ⁶ are bonded to each other to form an alkyl group having 3 to 10 carbon atoms. May form a ring.) 2. The resin A containing the structural unit (I) is obtained by protecting a part of the hydroxyl groups of polyvinylphenol with a protecting group represented by the formula (III). Positive radiation sensitive composition of. Embedded image (In the formula, R ⁴ , R ⁵ and R ⁶ have the same meaning as defined in claim 1.) 3. The resin B containing the structural unit (II) is a resin in which a part of the hydroxyl groups of polyvinylphenol is protected with a protecting group represented by the formula (IV). Positive radiation sensitive composition of. Embedded image wherein —CO—OR ¹⁰ ... (IV) (wherein R ¹⁰ has the same meaning as defined in claim 1) 4. The positive type according to claim 1, wherein in the resin A containing the structural unit (I), R ⁴ is an alkyl group having 1 to 10 carbon atoms and R ⁵ is a hydrogen atom. Radiation-sensitive composition. 5. The resin A containing the structural unit (I) has a δ value of 6. derived from aromatic hydrogen in a proton NMR spectrum.
The ratio of the peak area of 0 to 7.2 and the peak area of δ value 5.0 to 5.6 derived from hydrogen of acetal group is 8: 1 or more and 40: 1 or less. The positive-type radiation-sensitive composition according to claim 4. 6. 1 to 6 parts of a resin B containing the structural unit (II) relative to 100 parts by weight of a resin A containing the structural unit (I).
The positive-working radiation-sensitive composition according to claim 1, which comprises 0 to 5 parts by weight of 0.1 to 5 parts by weight of the compound C which generates an acid when exposed to radiation such as light or an electron beam. 7. The positive feeling according to claim 2, wherein the polystyrene reduced weight average molecular weight of polyvinylphenol which gives the resin A containing the structural unit (I) is 7,000 or more and 60,000 or less. Radioactive composition. 8. The positive feeling according to claim 3, wherein the polystyrene reduced weight average molecular weight of polyvinylphenol which gives the resin B containing the structural unit (II) is 1,000 or more and 60,000 or less. Radioactive composition.